Method and apparatus for making filter fabric



Oct. 15, 1940. w MANMNG 7 2,218,338

METHOD AND APPARATUS FOR MAKING FILTER FABRI'Z) Filed Spt. 5, 1936 2 Sheets-Sheet l Oct. 15, 1940. F. w. MANNING 2,218,338

METHOD AND APPARATUS FOR MAKING FILTER FABRIC Filed Sept. 5, 1936 2 Sheets-Sheen 2 I Patented Oct. 15, 1940 UNITED STATES METHOD AND APPARATUS ron MAKING m'rna mnmo Fred W. Manning, Pasadena, Calif., assignor to F. W. Manning Company, Ltd., Los Angeles, Calif., a corporation of California Application September 5, 1936, Serial No. 99,633

20 Claims.

My invention relates to equipment for manu-' sanitary napkins, wall board, artificial leather,

etc., and particularly fabrics adapted for use in filters.

It has been the practice heretfore to form sheets of fibrous material, such as paper, by slowly passing a fibre conveying liquid through a foraminous member of great area to deposit the fibres thereupon, the deposition resulting in a more or less clotted condition of fibres due to the degree of wetting or adhesion tension of the liquid against the fibres. If an elastic fluid is used for conveying purposes, a uniform distribution of most solids can be effected by the resistance of solids deposited over certain areas diverting the conveying fluid through less resistant solids deposited over other areas so that ultimately the distribution of the solids over the entire area becomes uniform. If, however, the fluid flow is very rapid and the solids ofier practically no resistance to the passage of the fluid through the retaining wall, the flow rate is greatly accelerated toward the center of the fluid stream, causing the 5 solids to pile up unevenly on the wall. Supplemental means must then be used to retard and distribute the solids just before the latter reach the wall. This can best be accomplished by using a primary, or surfacing, foraminous wall placed in close proximity and substantially parallel relation to the retaining wall, to collect the solids for distribution unto the retaining wall, the uniform distribution being efiected by a relative movement of the solids over the openings in the primary wall during passage of the fluid through both walls.

It is therefore an object of my invention to provide an improved method and means whereby a rapidly moving conveying fluid can be used to form a felted sheet of fibres of uniform thickness and porosity on a foraminous retaining wall of small area moving at comparatively great speed.

In accordance with my invention, fibrous material of vegetable, animal, or mineral origin, is introduced into a fiberizing machine as discrete fibres, or in web or other solid form. This fiberizing machine may consist of a hammer mill, card roll, or any other suitable means that will fluff, or separate one fibre from another, so that they may be dispersed in an elastic fluid and conveyed during dispersion from the fiberizing machine to a fabric forming machine, where most of the fibres are deposited on a foraminous surfacing wall and agitated thereover until finally conveyed through the openings in the wall and deposited on an adjacent wall in a uniformly distributed and felted condition by passage of the fluid through both walls. The movement of the fibres over the surfacing wall may be accomplished by the vibration of the wall. as illus- 5 trated in Figs. 1, 2 and 3 of my patent, Method of making filter fabric, Patent No. 2,152,901, dated April 4, 1939; or it may be accomplished by an agitating member, such as a brush, rake, or other convenient means, moving relatively and in con- 10 tact with, or in close proximity to, the wall, the rapid movement of the fibres over uniform openings in the wall under pressure of an elastic fluid causing the fibres to pass through the wall in a state of uniform distribution. The surfacing 15 wall may consist of any foraminous structure, preferably having an uneven or roughened surface, such as a screen; and such structure may be stationary but preferably moves in one direction, while the agitating member moves either in go the opposite direction or at a greater speed in the same direction. The retaining wall may consist of a porous flexible belt, open mesh fabric,

or other foraminous structure, which may also be stationary but preferably travels in substantially 25 parallel spaced relation with, and in the same direction as, the surfacing wall; and between the two walls may be drawn, or carried by movement of the surfacing and/or the retaining wall, reinforcing threads, which may be used to convey the so felted fibre sheet after its removal from between the two walls. Uniform feed of fibrous material, a constant air current. and regular movements of the depositing apparatus, will result in the formation of a felted sheet of uniform depth between the surfacing and retaining walls, but, if desirable, the entire space between the walls may be filled with fibres by movement of the incoming fibres over and through the surfacing wall under air pressure, and after once filled further compaction or consolidation of the deposited fibres may be increased by continuing this surfacing action. Excess fibres on the surfacing wall will be moved forward by the agitating member until the withdrawal movement of the felted sheet 45 from between the walls permits further fibres to enter therebetween.

The invention is exemplified in the following description, and a preferred arrangement is i1- lustrated by way of ,example in the accompany- 5o ing drawings, in which:

Fig.- 1 is a plan view of the complete equipment.

Fig. 2 is an elevational view of the complete equipment.

Fig. 3 is a vertical section of the deposition apparatus.

Fig. 4 is a cross-section of the deposition apparatus.

Fig. 5 is an elevational view of the deposition apparatus.

Fig. 6 is an end view of the deposition apparatus.

Fig. '1 is a cross-section of a modified arrangement of the surfacing and retaining walls of the deposition apparatus.

Fig. 8 is a cross-section of another modified arrangement of the surfacing and retaining walls of the deposition apparatus.

Fig. 9 is a fragmentary sectional view of the surfacing and retaining walls, showing how the depth of the space between the walls may be djusted.

Referring to the drawings more specifically by reference characters: In the preferred arrangement of motor, hammer mill, blower, and fabric machine, shown in Figs. 1 and 2, the roll of fibrous material I is supported by shaft 2 that turns in the bearings 3, the latter being bolted to the wooden frames 4. A web 5 from the roll is passed into the mill 5 by the feeding rolls 1, the speed of which may be regulated by the variable'speed transmission, 8, the latter being controlled by the operating wheel 9.- The mill shreds the fibres so that they are separated one from another, and also shortens them if they are long. The separated, or fiuifed, fibres are then carried through a piping connection I! into the blower H, the mill and blower being directly connected to the motor I2 by the shaft I3, and all supported by I beams l4. From the blower the fibres are carried through pipe connection l5 into the fibre deposing machine F, the filtered air from the latter being returned to the mill through the pipe connection I5.

Figs. 3 to 6 show the construction of the fibre depositing, or fabric machine, F. Left and right end plates I! and I8 respectively, support the screen l9, and the spacing bars 20,- which carry the scrim or retaining wall 2!, the combination forming the cage for separating and depositing the fibres from the air current. Trunnions 22 and 23 are attached to the exterior sides of the left and right hand end plates respectively, and rotate in bearings 24 and 25 respectively, which are bolted to the angle iron frames 25 and 21 respectively. Brackets 28 and 29 are fastened to the interior sides of the left and right hand end plates respectively to support the brush shaft 30, which is held in position by collars 3|, the former bracket forming a spider to permit entrance of the fibres and the latter bracket constructed similarly in case it is found desirable to introduce the air current from both sides. Angle irons 32 are fixed crosswise to the brush shaft, and to the ends of the former are fastened the brush bars 33 in contact with, or in close proximity to, the screen. The outer end of the brush shaft is supported by a bearing 34, which also forms a cap for the right hand trunnion. The shaft is driven by means of a sprocket wheel 35 on the outer end of former; sprocket chain 36; sprocket wheel 31 on a counter shaft 38, which is supported by a bearing bracket 39; spur gear 40, also on the counter shaft; and spur gear 4| on the main drive shaft 42, which is supported by bearing brackets 43 on the angle iron frames, and is driven from a source of power not shown. The screen cage is also driven from the main drive shaft, preferably in the opposite direction, by means of sprocket wheel 44 on the left hand trunnion and a sprocket wheel 45 on the drive shaft, which are connected together by the sprocket chain 46. The scrim enters the machine between the top roll 41 and the center roll 48, and after passing around the spacing bars, is removed with its fibre coating, as a filter fabric, or other felted sheet 49, between the center roll and the lower roll 50, by the rotation of the screen cage and pull on the scrim. Supporting plates 5| fastened to the hinged screen casing 52, hold the shaft of the center roll in fixed position, but the upper and lower rolls are held in spring resistant contact therewith by means of the elongated openings 53 through which project the shafts of the rolls, coil springs 54 being attached to the ends of the shafts, and the fixed pins 55 in the supporting plates. As shown in Fig. 2, the scrim may be subjected to an atomizing spray from nozzle 56 within an enclosure 51 before passing into the fabric machine; and the coated scrim may be subjected to another atomizing spray from a nozzle 58 within an enclosure 59, after leaving the machine and before passing over and/or between calendering and drying rolls 60, GI and 52.

Fig. 7 shows a modified arrangement in which warp reinforcing threads 63, without weft threads, pass around the screen cage and out as a filter fabric 54, a scrim or other open mesh fabric 55 being used as a foraminous retaining wall to support the warp threads and aid the latter in retaining the fibres until a felted sheet has been formed about the threads that can be separated from the open mesh fabric. In this arrangement the open mesh fabric forms an endless belt, which is returned by being passed back over the rolls 56, the filtered air being removed through the chamber 61 into the return pipe leading to the mill.

Fig. 8, shows another modified arrangement in which the supporting open mesh fabric, or foraminous retaining wall for the warp threads is supplied from a roll 58 and returned to a roll 69, the latter being changed to the position of the former and becoming the supply roll when the former is exhausted.

Fig. 9 shows an arrangement whereby the depth of the space between the surfacing wall and retaining wall may be adjusted by moving the rods 10 in the slots H, shown in Figs. 7 and 8, and locking them in position by nuts I2. In this case the screen, or surfacing wall, is attached and wholly supported by the end plates.

The operation of the apparatus thus constructed has been in part indicated in connection with the foregoing description. Fibrous material in the form of a web from roll I is fed into the fiberizing machine where the fibres are separated, and sometimes shortened, and then picked up by an air current and carried into the blower from which they are blown through pipe l5 into the fabric machine where they are retained on they surfacing wall until sifted through uniform openings unto the retaining wall by movement of the brush over the surfacing wall and passage of the air through both walls. As shown in Figs. 1 and 2, the scrim, or other open mesh fabric, may be sized in a previous operation and dampened as it is drawn into the fabric machine; or the scrim may be subjected as it enters the fabric machine, to an atomized spray of adhesive, preferably having adsorptive characteristcs, such as a sodum slicate solution; or,

aaraacs meileaving the fabric machine, the reinforced side of the felted sheet may be treated in the same way-before being passed over and between the drying and calendering rolls to bond the fibres together and to their reinforcing threads.

The surfacing and retaining walls are driven from the main drive shaft and the slack between the fabric machine and calender rolls is taken up by the latter, which may be driven by a fricac tion clutch not shown. However, when no reinforcing threads are used, the speed of the rolls must be synchronized with the speed of the re= taining wall in order that the pull in sheet be not excessive.

It will be obvious from the foregoing description that the reinforcing threads may also serve as the foraminous retaining wall; or the retaining wall may serve simply as a support for the reinforcing threads, or other open mesh structure, until the fibres are sufliciently felted thereto for the support to be withdrawn; or the reinforcing threads shown at 63 in Fig. 7, may be eliminated entirely and the fibres felted to the foraminous wall until the sheet is of sufficient strength for its retaining wall support to be withdrawn. 1

It will also be evident that the felted sheet may vary in thickness between the surfacing wall and the retaining wall, and that this thickness will depend on the velocity of the air current, amount of fibres in the air current, relative movement of the agitating member as compared with the movement of the surfacing wall, and

the felted the speed of the retaining wall; or if the space between the surfacing and retaining walls is completely filled with felted fibres, further consolidation of the fibres may be accomplished by continuing the movement of the fibres over the surfacing wall and passage of the air current through the felted fibres before withdrawing the felted sheet from the fabric machine.

It will furthermore be evident that increasing the relative movement of the agitating member on a foraminous wall having an uneven surface will greatly accelerate the passage of the fibres through the wali under pressure of an elastic fluid, and for this reason the agitating member is usually moved in the opposite direction to that of the wall. If still greater agitation of the fibres is required, the brushes as well as the brush arms may be made to rotate.

Itwill still furthermore be evident that a granular solid, such as diatomaceous earth, or a decolorizing carbon or clay, may be incorporated in the felted sheet by either incorporating the agent in the web fed to the fiberizing. machine, or by feeding such agent separately into either the fiberizing machine or the suction of the blower.

I claim as my invention:

1. In an apparatus for making a felted sheet, the combination of: a foraminous surfacing wall and a foraminous retaining wall; means for moving the retaining wall in substantially parallel moving the agitating member and surfacing wall relatively and in contact with each other; a foraminousretaining wall; means for moving reinforcing threads between the surfacing wall and the retaining wall; and means for creating a fluid current whereby the flow of the said fluid and the relative movement of the agitating memher and surfacing wall cause a fibrous material to bepassed through the surfacing wall, and deposited on the reinforcing threads in a feltedv sheet. of uniform depth.

3. In an apparatus for making a composite fabric, the combination of: an agitating member; a foraminous surfacing wall; means for moving the agitating member and surfacing wall relatively and in contact with each other; a forminous retaining wall; means for moving reinforcing threads between the surfacing wall and the retaining wall; and means for creating a flow of elastic fluid whereby the flow of the said fluid and the relative movement of the agitating memher and surfacing wall cause a fibrous material to be passed through the surfacing wall and deposited on the reinforcing threads in a felted sheet of uniform depth.

4. In an apparatus for making a composite fabric, the combination of a fiberizing machine; a blower; an agitating member; a ioraminous surfacing wall; means for moving the agitating member and surfacing wall relatively and in contact with each other; a foraminous retaining wall; means for moving reinforcing threads between the surfacing wall and the retaining wall;

and means for introducing fibrous material, whereby the said material is separated into discrete fibres by the fiberizing machine, the discrete fibres dispersed by a current of elastic fluid from the blower, and the dispersed fibres passed through the surfacing wall and deposited on the reinforcing threads by the flow of the said fluid and relative movement of the agitating member and surfacing wall.

5. In an apparatus for making a composite fabric, the combination of: an agitating member; a foraminous surfacing wall; means for moving the agitating member and surfacing wall relatively and in contact with each other; a foraminous retaining wall; means for moving reinforcing threads between the surfacing wall and the retaining wall; a fiberizing machine for fiumng fibrous material; and means for creating a flow of elastic fluid from the fiberizing machine through the surfacing and retaining walls, whereby the flow of the said fluid and the relative movement of the agitating member and the sur-. facing wall cause fibres flufied by the fiberizing machine to be dispersed, passed through the surfacing wall, and deposited on the reinforcing threads in a felted sheet of uniform depth.

6. In an apparatus for making a composite fabric, the combination of :an agitating member; a ioraminous surfacing wall; means for moving the agitating member and surfacing wall relatively and in contact with each other; a foruminous retaining wall; means for moving reinforcing threads between the surfacing wall and the retaining wall; a fiberizing machine for flufing 7. 'Ihe method of making a felted sheet of tin!- formly distributed fibres, comprising: agitating a discrete fibrous material on a primary foraminous wall to aid the sifting of the material through the adjacent secondary foraminous wall moving in substantially parallel spaced relation to the primary wall, while passing a conveying fluid through both walls. v

8. The method of making a felted sheet of uniformly distributed fibres, comprising: agitating a discrete fibrous material on a primary foraminous wall to aid the sifting of the material through the wall; depositing the sifted material on an adjacent secondary foraminous wall moving in substantially parallel spaced relation to the primary wall. while passing a conveying fluid through both walls; and removing the felted sheet from between the sald walls.

9. The method of making a felted sheet of uniformly distributed fibres, comprising: depositing a fibrous material on a primary foraminous wall; moving the deposited material along the primary wall; and sifting the material through the said primary wall and depositingthe sifted material on an adjacent secondary foraminous wall positioned in substantially parallel spaced relation to the primary wall, while passing an elastic fluid through both walls.

10. .The method of making a felted sheet of uniformly distributed fibres, comprising: sifting a fibrous material through a primary foraminous wall and depositing the sifted material on an adjacent secondary foraminous wall moving in substantially parallel spaced relation to the primary wall, while passing an elastic fiuid through both walls: and continuously removing the felted sheet from between the said walls. y

11. The method of making a felted sheet of uniformly distributed fibres, comprising: depositing a fibrous material on a. foraminous surfacing wall; sifting the deposited material through the surfacing wall; depositing the sifted material on an adjacent foraminous retaining wall positioned in substantially parallel spaced relation to the surfacing wall, while passing a conveying fluid through both walls; and continuously removing the felted sheet from between the said walls.

12. The method of making a felted sheet of uniformly distributed fibres, comprising: sifting a fibrous material through a moving foraminous surfacing wall; depositing the sifted material on an adjacent foraminous retaining wall positioned in substantially parallel spaced relation to the surfacing wall, while passing a conveying fluid through both walls; and continuously removing the felted sheet from between the said walls.

13. The method of making a felted sheet of uniformly distributed fibres, comprising: sifting a fibrous material through a moving foraminous surfacing wall; depositing the sifted material on an adjacent foraminous retaining wall moving in substantially'parallel spaced relation to the surfacing wall, while passing a conveying fluid through both walls; and continuously removing the felted sheet from between the said walls.

14. The method of making a felted sheet of uniformly distributed fibres, comprising: reducing a fibrous web material to discrete fibres in the presence of a fluid; sifting the discrete fibres through a foraminous surfacing wall and depositon the reinforcing threads ina felted sheet of uniform depth,

ment of the fibres on the surfacing wall and pas sage of the fluid through both walls; and remov-- I ing the felted sheet from between the said walls. wall; and depositing thesifted materiab on an 15. The method of making a felted sheet of uniformly distributed fibres, comprising: dispersing fibrous material in the presence of an elastic fluid; sifting the dispersed fibres through a foraminous surfacing wall and depositing the sifted fibres on an adjacent foraminous retaining wall moving in substantially parallel spaced relation to the surfacing wall", by movement of the fibres over the surfacing wall and. passage of. the fluid through both walls; and removing the felted sheet from between the saidwalls.

16. In an apparatus for making a felted sheet, the combination of a foraminous surfacing wall and a foraminous retaining wall positioned in substantially parallel spaced relation to each facing wall and an adjacent and substantiallyv parallel spaced foraminous retaining wall by depositing a fibrous material on the face of the surfacing wall and moving the deposited material along the surfacing wall while passing an elastic fluid through both walls.

. 18. The method of makings felted sheet of uniformly distributed fibres, comprising: filling the spacing between the face of a foraminous surfacing wall and an adjacent and substantially parallel spaced foraminous retaining wall by moving a fibrous material over the face of the surfacing wall while passing an elastic fluid I through both walls; and continuously removing the felted sheet from between the said walls.

19. In an apparatus for making a felted sheet, the combination of a cylindrical foraminous surfacing wall and a cylindrical foraminous retaining wall positioned adjacent and concentric to each other; means for moving discrete solids over the surfacing wall; and means for passing an elastic fluid through both walls simultaneously with the movement of the solids over the surfacing wall, whereby the solids are distributed through the surfacing wall and deposited uniformly on the retaining wall.

20. In an apparatus for makmg a felted sheet. the combination of: a cylindrical foraminous surfacing wall and a cylindrical foraminous retaining wall positioned adjacent and concentric to each other; means for moving discrete solids over the surfacing wall; means for passing an elastic fluid through both walls simultaneously with the whereby the solids are distributed through the surfacing wall and deposited uniformly on the retaining wall; and means for continuously removing the felted sheet from between the said walls.

' FRED W. MANNING.

-movement of the solids over the surfacing-wall, j 

